<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item,index) in levelList" :key="item.path">
        <span v-if="item.redirect==='noRedirect'||index==levelList.length-1" class="no-redirect">{{ item.meta.title }}</span>
        <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script>
import pathToRegexp from 'path-to-regexp'

export default {
  data() {
    return {
      levelList: null
    }
  },
  watch: {
    $route(route) {
      // if you go to the redirect page, do not update the breadcrumbs
      if (route.path.startsWith('/redirect/')) {
        return
      }
      this.getBreadcrumb()
    }
  },
  mounted() {
    this.getBreadcrumb()
  },
  methods: {
    getBreadcrumb() {
      let params = JSON.parse( sessionStorage.getItem(this.$route.path) )
      if(params && params.breadcrumb != [] && params.breadcrumb != undefined){
        this.levelList = params.breadcrumb
      }else{
        // only show routes with meta.title
        let matched = this.$route.meta && this.$route.meta.pmatched 
                      ? Array.from( new Set( this.$route.meta.pmatched.concat(this.$route.matched) ) ) 
                      : this.$route.matched
        matched = matched.filter(item => item.meta && item.meta.title)
        const first = matched[0]

        if (!this.isDashboard(first)) {
          // matched = [{ path: '/index', meta: { title: '首页' }}].concat(matched)
        }

        this.levelList = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false)
        this.$route.meta.breadcrumb=this.levelList.map(item=>{
          const new_item={
            path:item.path,
            meta:{title:item.meta.title},
            redirect:item.redirect
          }
          return new_item
        })
      }
    },
    isDashboard(route) {
      const name = route && route.name
      if (!name) {
        return false
      }
      return name.trim() === '首页'
    },
    pathCompile(path) {
      const { params } = this.$route
      var toPath = pathToRegexp.compile(path)
      return toPath(params)
    },
    handleLink(item) {
      const { redirect, path } = item
      if (redirect) {
        this.$router.push(redirect)
        return
      }
      this.$router.push(this.pathCompile(path));
    }
  }
}
</script>

<style lang="scss" scoped>
.app-breadcrumb.el-breadcrumb {
  display: inline-block;
  font-size: 14px;
  line-height: 50px;
  margin-left: 8px;

  .no-redirect {
    color: #fff;
    cursor: text;
  }
}
</style>
